Fix for stringized function-macro args continued across lines

In case of certain #define'd macros, there's a space just before line continuation
that the minimized-source lexer was missing to include, resulting in invalid stringize.

Patch by: kousikk (Kousik Kumar)

Differential Revision: https://reviews.llvm.org/D67635

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@372360 91177308-0d34-0410-b5e6-96231b3b80d8
(cherry picked from commit 6fc00ec)

lib/Lex/DependencyDirectivesSourceMinimizer.cpp

@@ -246,9 +246,12 @@ static void skipToNewlineRaw(const char *&First, const char *const End) {
 
 static const char *reverseOverSpaces(const char *First, const char *Last) {
   assert(First <= Last);
-  while (First != Last && isHorizontalWhitespace(Last[-1]))
+  const char *PrevLast = Last;
+  while (First != Last && isHorizontalWhitespace(Last[-1])) {
+    PrevLast = Last;
     --Last;
-  return Last;
+  }
+  return PrevLast;
 }
 
 static void skipLineComment(const char *&First, const char *const End) {

unittests/Lex/DependencyDirectivesSourceMinimizerTest.cpp

@@ -157,19 +157,19 @@ TEST(MinimizeSourceToDependencyDirectivesTest, DefineHorizontalWhitespace) {
 
   ASSERT_FALSE(minimizeSourceToDependencyDirectives(
       "#define MACRO(\t)\tcon \t tent\t", Out));
-  EXPECT_STREQ("#define MACRO() con \t tent\n", Out.data());
+  EXPECT_STREQ("#define MACRO() con \t tent\t\n", Out.data());
 
   ASSERT_FALSE(minimizeSourceToDependencyDirectives(
       "#define MACRO(\f)\fcon \f tent\f", Out));
-  EXPECT_STREQ("#define MACRO() con \f tent\n", Out.data());
+  EXPECT_STREQ("#define MACRO() con \f tent\f\n", Out.data());
 
   ASSERT_FALSE(minimizeSourceToDependencyDirectives(
       "#define MACRO(\v)\vcon \v tent\v", Out));
-  EXPECT_STREQ("#define MACRO() con \v tent\n", Out.data());
+  EXPECT_STREQ("#define MACRO() con \v tent\v\n", Out.data());
 
   ASSERT_FALSE(minimizeSourceToDependencyDirectives(
       "#define MACRO \t\v\f\v\t con\f\t\vtent\v\f \v", Out));
-  EXPECT_STREQ("#define MACRO con\f\t\vtent\n", Out.data());
+  EXPECT_STREQ("#define MACRO con\f\t\vtent\v\n", Out.data());
 }
 
 TEST(MinimizeSourceToDependencyDirectivesTest, DefineMultilineArgs) {
@@ -187,7 +187,7 @@ TEST(MinimizeSourceToDependencyDirectivesTest, DefineMultilineArgs) {
                                            "        call((a),      \\\n"
                                            "             (b))",
                                            Out));
-  EXPECT_STREQ("#define MACRO(a,b) call((a),(b))\n", Out.data());
+  EXPECT_STREQ("#define MACRO(a,b) call((a), (b))\n", Out.data());
 }
 
 TEST(MinimizeSourceToDependencyDirectivesTest,
@@ -200,7 +200,17 @@ TEST(MinimizeSourceToDependencyDirectivesTest,
                                            "        call((a),      \\\r"
                                            "             (b))",
                                            Out));
-  EXPECT_STREQ("#define MACRO(a,b) call((a),(b))\n", Out.data());
+  EXPECT_STREQ("#define MACRO(a,b) call((a), (b))\n", Out.data());
+}
+
+TEST(MinimizeSourceToDependencyDirectivesTest, DefineMultilineArgsStringize) {
+  SmallVector<char, 128> Out;
+
+  ASSERT_FALSE(minimizeSourceToDependencyDirectives("#define MACRO(a,b) \\\n"
+                                                    "                #a \\\n"
+                                                    "                #b",
+                                                    Out));
+  EXPECT_STREQ("#define MACRO(a,b) #a #b\n", Out.data());
 }
 
 TEST(MinimizeSourceToDependencyDirectivesTest,
@@ -213,7 +223,7 @@ TEST(MinimizeSourceToDependencyDirectivesTest,
                                            "        call((a),      \\\r\n"
                                            "             (b))",
                                            Out));
-  EXPECT_STREQ("#define MACRO(a,b) call((a),(b))\n", Out.data());
+  EXPECT_STREQ("#define MACRO(a,b) call((a), (b))\n", Out.data());
 }
 
 TEST(MinimizeSourceToDependencyDirectivesTest,
@@ -226,7 +236,7 @@ TEST(MinimizeSourceToDependencyDirectivesTest,
                                            "        call((a),      \\\n\r"
                                            "             (b))",
                                            Out));
-  EXPECT_STREQ("#define MACRO(a,b) call((a),(b))\n", Out.data());
+  EXPECT_STREQ("#define MACRO(a,b) call((a), (b))\n", Out.data());
 }
 
 TEST(MinimizeSourceToDependencyDirectivesTest, DefineNumber) {